odds are just mathematic probabilities. Could be one, could be a thousand in real life.
genetic roulette and that's the fun part
If the recessive traits are expressed they are fixed in the phenotype of all future uncrossed offspring.
Trouble is often more than one gene is at work in such characteristics as shape and color so it is difficult to predict ahead of time, especially if you do not know the exact pedigree of the parent plants. and then of course there is taste, maturity, production, disease susecptability.... honestly its a crapshoot stabilizing an OP tomato probabilities notwithstanding.
Bottom line is grow out as many as you have room for and hope that among them is something worth working on. Keep an open mind as you might find something that is actually better than what you are trying for... If not, grow them out again for round two of f2 selection or back to the drawing board and make a new cross.
Don't let this or anyone else discourage you. It's fun! good luck!
KarenO